Moisture removing stack cap for engine air intakes

ABSTRACT

A centrifugal separator is shown, including a collector tube that is large enough to fit over the top end of a vertically extending engine air intake stack to provide a moisture collecting chamber between the walls of the stack and tube; a stack cap base member with a central opening connected to the tube and walls with air intake openings therein flaring outwardly from the central opening; a cover member mounted over the base member to form a chamber therebetween; and a plurality of spaced, tangentially directed vanes mounted in the chamber between the intake openings and central opening.

Waited States Lidstone [451 Feb. 112, 1974 MOISTURE REMOVING STACK CAPFOR ENGHNE AIR INTAKIES [75] Inventor: James E. Lidstone, St. LouisPark,

Minn.

[73] Assignee: Donaldson Company line,

Minneapolis, Minn.

[22] Filed: Sept. 23, 1971 [21] App]. No.: 182,962

[52] US. Cl 55/385, 55/337, 55/396, 55/419, 55/450, 55/456, 55/459,55/DlG. 28 [51] Int. Cl. 1304c 3/06 [58] Fieldol'Search ..55/337,D1G.27,DIG. 28, 55/447-457, 385, 498, 396, 419, 459

[56] References Cited UNITED STATES PATENTS 1,664,683 4/1928 Hawley55/455 X 2,804,169 8/1957 Olah 55/450 FOREIGN PATENTS OR APPLICATIONS542,186 4/1956 Italy 55/337 896,609 5/1944 France 55/323 PrimaryExaminer-Dennis E. Talbert, Jr. Attorney, Agent, or FirmMerehant, Gould,Smith & Edell ABSTRACT A centrifugal separator is shown, including acollector tube that is large enough to fit over the top end of avertically extending engine air intake stack to provide a moisturecollecting chamber between the walls of the stack and tube; a stack capbase member with a central opening connected to the tube and walls withair intake openings therein flaring outwardly from the central opening;a cover member mounted over the base member to form a chambertherebetween; and a plurality of spaced, tangentially directed vanesmounted in the chamber between the intake openings and central opening.

7 Claims, 3 Drawing Figures PATENTEDFEB i 2 1924 I 3791; 112

7&1

J5 INVENTOR /%cm;m 7 e' Jana J3 z/- arm/mam MOISTURE REMOVING STACK CAPFOR ENGINE AIR INTAKES BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates generally to devices for removingmoisture from the air, and more particularly relates to a stack caphaving vanes positioned to rotate the air passing downwardly through acollector tube, to thereby centrifugally force the moisture outwardlyagainst the walls of the tube for collection and disposal.

2. Description of the Prior Art Many vehicles employing internalcombustion engines, such as farm tractors, highway trucks and earthmoving equipment, employ heavy-duty air cleaners to separate and filterdirt from the air being drawn into the engine. In many applications, theair is drawn into the air cleaner through a vertically extending stackhaving an open top end. It has been common practice to provide a cap formounting on the stack to prevent rain or snow from entering the stack,while permitting a free flow of air to the stack opening. In someinstances, the stack cap has been provided with screens or separatingdevices designed to remove some dirt from the air before it reaches theprimary filter. An example ofa stack cap performing a centrifugalpre-cleaning function is shown in the Takashi Araki U.S. Pat. No.3,552,102 that issued Jan. 5, 1971. In the Araki patent, the air entersthe stack cap chamber through fins, causing it to swirl within thechamber. Centrifugal force causes the heavier dirt particles to bethrown upwardly and outwardly into a collecting chamber, while the main,now cleaner air stream passes downwardly into the air intake stack.Other patents showing similar structures are Donaldson U.S. Pat Nos.1,641,746, Cresswell 2,304,778, Kegerreis et a]. 1,934,311, and Russell2,417,130. In all of these prior art patents, the air enters the bottomof a dome-like structure through a plurality of fins that cause the airto swirl around the interior of the dome. The heavy dirt particles arethus thrown outwardly so that they can be collected. The clean air isdrawn to the center and from there flows downwardly through a verticaltube.

The structures of these prior art patents do not completely remove waterparticles from the air stream during heavy rainfall conditions. Althoughthe dome will prevent most of the rain water from entering the stack,some water will always be carried into the stack. This moisture-ladenair may interfere with combustion or may degrade the performance of theair filter. Although the structures shown in the above-identifiedpatents will remove dirt particles from the air, they will not removeany significant amounts of moisture.

Some of the prior art systems as described above, have been modified toseparate moisture from the air by placing a set of spirally arrangedfins within the stack or an extension thereof. The spiral fins withinthe tube cause the air to swirl so that the moisture impinges andcollects on the interior of the tube. The problem with the vaned tubeshas been the excessive cost of production and some undesirable increasein restriction to air flow through the tubes.

SUMMARY OF THE INVENTION The present invention provides a new and uniqueform of stack cap having simple, effective and inexpen sive means ofremoving moisture from the air, without significantly reducing air flow.The stack cap includes a dome-like cover and a base member forming achamber therebetween. The base member has a central opening to which isconnected a collector tube. The collector tube is designed to fit overthe top of a stack and is sufficiently large to provide a collectingchamber between the stack and the collector tube. The base member isprovided with air intake openings, and a plurality of spaced, airdirecting vanes are mounted in the chamber in a generally tangentialrelationship with respect to the central opening. Air is drawn by theengine through the intake openings, past the vanes and downwardlythrough the collector tube and stack. The vanes direct the air so thatit enters the collector tube tangentially and thus rotates downwardlythrough the tube. Centrifugal force causes moisture particles in the airstream to impinge on the walls of the collector tube, from where itdrains downwardly into the collecting chamber. The collecting chamber isprovided with a drain opening. The central column of air from whichmoisture has been removed passes downwardly through the stack into theair cleaner and engine. Tests have shown that this system is veryefficient in removing excess moisture from the air stream and that thevanes offer very little restriction to air flow. Further, when comparedwith the vaned tubes, the cost of manufacturing the present system isreduced by about 50 percent. Therefore, in summary, the presentinvention provides equal or improved performance as compared to thevaned tubes, is considerably lower in cost than the prior art system andcauses considerably less restriction to air flow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation ofamoisture removing cap mounted on a typical air cleaner air intake stack,portions thereof being broken away and shown in section;

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1,portions thereof being broken away; and

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1, portions ofthe background structure having been removed.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,wherein like reference numerals are used throughout the several views toindicate like elements of the invention, there is disclosed in FIG. 1 anair cleaner 10 having a cylindrical body with an air intake tube 11 atthe upper end and an air outlet tube 12 in a side wall thereof. Mountedwithin the air cleaner 10 is a cylindrical filter element 13. Air outlettube 12 would be connected to the air intake of an internal combustionengine. The air would be drawn by the engine through tube 1 l, filterelement 13 and tube 12.

Connected to air intake tube 11 is a vertically oriented, cylindricalintake stack 14. In the preferred embodiment, air intake stack 14 is inthe form of a cylinder. Mounted over the top end of stack 14 is acollector tube 15, also in the form of a cylinder. Tube 15 has a largercross-sectional dimension or diameter than the corresponding dimensionof stack 14 thereby providing an annular moisture collecting chamber 16between a bottom portion of tube and stack 14. Chamber 16 is an annularchamber having an inwardly sloping bottom wall 17 with a drain opening18 therein. The inner edge of bottom wall 17 is clamped or otherwisesecured to the outer wall of stack 14. A plurality of spacer members 19are mounted between tube 15 and stack 14 to maintain the coaxialalignment.

Mounted on the top end of collector tube 15 is a stack cap 20 having abase member 21 and a cover member 22. In the preferred embodiment, basemember 21 and cover member 22 are molded from a suitable thermoplasticmaterial. Base member 21 includes a tubular mounting flange 23 defininga central opening 24. Mounting flange 23 extends over the top ofcollector tube 15 and is secured thereto by means of a band 25. Centralopening 24 has approximately the same diameter as the interior diameterof tube 15 so that smooth air flow into the tube is insured.

Base member 21 also includes a funnel-shaped wall 21a, flaring upwardlyand outwardly from central opening 24, and terminating in a peripheral,horizontally extending portion 21b. Portion 21b is circular in shape.Wall 21a and portion 21b are formed to have a large plurality ofopenings 26 therein, the openings 26 forming a screen-like air intakeportion around the entire base member. Extending downwardly from theouter edge of portion 21b is cylindrical wall 27 having a bottom edgeextending below the level of openings 26. Wall 27 acts as a shield toprevent rain and snow from directly entering openings 26.

Cover member 22 is a dome-like structure having a horizontally extendingperipheral flange 30, circular in shape, positioned over portion 21!).As best shown in FIG. 1, base member 21 and cover member 22 thus definean air flow chamber 31 within the stack cap 20.

A plurality of air directing vanes 32 are mounted within chamber 31.Each of the vanes 32 has a flat, horizontally extending connectorportion 32a and a vertically extending, planar blade portion 32b. In thepreferred embodiment, eight vanes 32 are evenly spaced around theperiphery of chamber 31 with the connector portion 32a of eachpositioned between portion 21b and flange 30. The connector portions 32aare frictionally retained in a predetermined position therebetween byrivets 33 extending therethrough. When portion 21b and flange areriveted together with the connector portions therebetween, some slightdeformation of the parts occurs to retain the vanes in predeterminedpositions.

The blade portions 32b each lie in a separate vertical plane thatextends generally tangentially with respect to the central opening 24.Each blade portion 32b has an upper edge positioned closely adjacent thecover member 22 and a lower edge psoitioned closely adjacent base member21 and openings 26. In this embodiment, each blade portion 32b has avertical innermost edge positioned between the intake openings 26 andthe central opening 24. Vanes 32 are preferably constructed fromplastic, but could be constructed from metal as well. Further, vanes 32could be molded to the inner surface of either cover member 22 or basemember 21 without departing from the invention.

It is noted that cover member 22 has an outwardly and downwardlyextending lip 34 depending from flange 30. Water running from off thetop of cover member 22 thus normally drains off the bottom edge of lip34 without coming in contact with wall 27, and a sufficient distanceaway from air intake openings 26 so as not to be entrained in theincoming air stream. It is further noted that portion 21b and flange 30are spaced apart between the connector portions 32a a distancecorresponding to the thickness of the connector portions. Therefore,some air can enter chamber 31 between them as well as through openings26.

During engine operation, air is drawn inwardly through openings 26 at arelatively high velocity. The air is directed by the vanes so that theair stream leaving each vane enters opening 24 and tube 15 generallytangentially with respect thereto. Because the air is traveling at ahigh velocity, the vanes cause it to swirl or rotate as it passesdownwardly through tube 15. This rotation of the air stream causes acentrifugal force to be applied to any water droplets or other moistureparticles being carried by the air stream. The moisture particles arethrown outwardly and impinge on the inner wall of collector tube 15,where they collect and drain downwardly into collecting chamber 16. Thecollected moisture drains to atmosphere through opening 18. The airstream from which the moisture has been removed thus enters stack 14leading to air cleaner 10. Some varients in the positioning and form ofthe vanes 32 can be permited without departing from the invention. Thefunction of the vanes is to direct the air stream tangentially into thecentral opening so that the air stream and moisture carried therebyimmediately impinge upon the inner wall of collector tube 15. Because ofthe high velocity swirling action and because the air immediatelyimpinges upon the top end of the tube 15, only a relatively shortsection of collector tube 15 is required to effectively separatemoisture from the air stream. My invention is defined in the followingclaims.

What is claimed is:

1. In a moisture removing stack cap having a collector tube adapted tobe mounted over a vertically oriented engine air intake stack, saidstack cap including a base member having a central opening connected toone end of said tube and a wall flaring outwardly from said centralopening with air intake openings therein and terminating in a peripheraledge, and further including a cover member having a peripheral edgeconnected to the edge of said base member, forming a chamber betweensaid base member and cover member permitting air to flow from said airintake openings through said chamber to said tube, the improvementcomprising; a plurality of spaced, air directing vanes secured to saidstack cap in said chamber and positioned between said air intakeopenings and said central opening to rotate the air as it passes intoand downwardly through said collector tube thereby causing moisture inthe air to impinge on and flow down the walls of said tube to separatethe moisture from the air stream, said peripheral edges having matingflanges, and said vanes each having a connector oortion secured betweensaid flanges and a blade portion extending therefrom toward said centralopening.

2. The apparatus of claim 1 wherein each of said blade portions lie in aplane extending generally tangentially with respect to said centralopening.

3. The apparatus of claim 2 wherein said blade portions each have anupper edge positioned closely adjacent said cover member and a loweredge positioned closely adjacent said base member.

4. A moisture removing stack cap adapted to be mounted over a verticallyoriented engine air intake stack, comprising:

a. a collector tube adapted to fit over the top end of a stack toprovide an annular chamber between the walls of the tube and stack;

b. a stack cap base member having a central opening connected to the topend of said tube, and a wall flaring outwardly from said centralopening, said wall having air intake openings, therein and terminatingin a peripheral flange;

c. a dome-like stack cap cover member having a peripheral flangepositioned over the flange of said base member, forming an air flowchamber be tween said base member and cover member;

(1. a plurality of spaced, air directing vanes each having a connectorportion positioned between said flanges and a blade portion extendingtherefrom toward said central opening; and

e. means for tightly securing said flanges together to retain saidconnector portions of said vanes therebetween, said vanes beingpositioned to cause said air to rotate as it passes into and downwardlythrough said collector tube thereby causing moisture in the air toimpinge on and flow down the walls of said tube to separate the moisturefrom the air stream. n

5. The apparatus of claim 4 wherein said blade portions are generallytangentially positioned with respect to the central opening.

6. A moisture removing stack cap for a vertically oriented, cylindricalengine air intake stack, comprising:

a. a cylindrical collector tube having a larger cross sectionaldimension than the stack;

b. means mounting said collector tube with a bottom portion thereofextending over a top end of said stack, providing an annular moisturecollecting and discharging chamber between said tube and said stack, atop portion of said tube extending above said stack;

0. a stack cap base member, mounted on a top end of said tube, having acentral opening over said tube and wall flaring upwardly and outwardlyfrom said central opening, said wall having air intake openings thereinand terminating in a peripheral flange;

d. dome-like stack cap cover member having a peripheral flangepositioned over the flange of said base member, thereby forming an airflow chamber between said base member and cover member;

e. a plurality of air directing vanes each having a flat horizontallyextending connector portion positioned between said flanges, and avertically positioned blade portion extending therefrom toward saidcentral opening in a plane generally tangential with respect to saidcentral opening, said vanes being evenly spaced around the periphery ofsaid stack cap; and

f. means for tightly clamping said flanges together to frictionallyretain said connector portions of said vanes therebetween, said vanescausing said air to rotate as it passes into and downwardly through saidcollector tube thereby causing water into the air to impinge on thewalls of said tube and flow downwardly into said annular chamber.

7. A moisture removing stack cap having a genrally cylindrically shapedcollector tube with first and second end portions, said first endportion being adapted to be mounted over a vertically oriented engineair intake stack, said second end portion extending vertically upwardlywhen mounted and having a smooth interior cylindrically shaped wallsurface extending to an upper end of said tube, said stack cap includinga base member having a central opening of approximately the samediameter as the interior diameter of said tube, means connecting saidupper end of said tube directly to an edge of said central opening toprovide a smooth air flow path into said tube, said base member furtherincluding a wall flaring outwardly from said central opening with airintake openings therein and terminating a peripheral edge, and saidstack cap including a cover member having a peripheral edge connected tothe peripheral edge of said base member, forming a chamber between saidbase member and cover member permitting air to flow from said air intakeopenings throug said chamber to said tube, a plurality of spaced airdirecting vanes secured to said stack cap and positioned in said chamberbetween said air intake openings and said central opening to rotate theair as it passes into and downwardly through said collector tube therebycausing moisture in the air to impinge on and flow down the smoothinterior wall surface of said tube to separate the moisture from the airstream.

1. In a moisture removing stack cap having a collector tube adapted tobe mounted over a vertically oriented engine air intake stack, saidstack cap including a base member having a central opening connected toone end of said tube and a wall flaring outwardly from said centralopening with air intake openings therein and terminating in a peripheraledge, and further including a cover member having a peripheral edgeconnected to the edge of said base member, forming a chamber betweensaid base member and cover member permitting air to flow from said airintake openings through said chamber to said tube, the improvementcomprising; a plurality of spaced, air directing vanes secured to saidstack cap in said chamber and positioned between said air intakeopenings and said central opening to rotate the air as it passes intoand downwardly through said collector tube thereby causing moisture inthe air to impinge on and flow down the walls of said tube to separatethe moisture from the air stream, said peripheral edges having matingflanges, and said vanes each having a connector oortion secured betweensaid flanges and a blade portion extending therefrom toward said centralopening.
 2. The apparatus of claim 1 wherein each of said blade portionslie in a plane extending generally tangentially with respect to saidcentral opening.
 3. The apparatus of claim 2 wherein said blade portionseach have an upper edge positioned closely adjacent said cover memberand a lower edge positioned closely adjacent said base member.
 4. Amoisture removing stack cap adapted to be mounted over a verticallyoriented engine air intake stack, comprising: a. a collector tubeadapted to fit over the top end of a stack to provide an annular chamberbetween the walls of the tube and stack; b. a stack cap base memberhaving a central opening connected to the top end of said tube, and awall flaring outwardly from said central opening, said wall having airintake openings, therein and terminating in a peripheral flange; c. adome-like stack cap cover member having a peripheral flange positionedover the flange of said base member, forming an air flow chamber betweensaid base member and cover member; d. a plurality of spaced, airdirecting vanes each having a connector portion positioned between saidflanges and a blade portion extending therefrom toward said centralopening; and e. means for tightly securing said flanges together toretain said connector portions of said vanes therebetween, said vanesbeing positioned to cause said air to rotate as it passes into anddownwardly through said collector tube thereby causing moisture in theair to impinge on and flow down the walls of said tube to separate themoisture from the air stream.
 5. The apparatus of claim 4 wherein saidblade portions are generAlly tangentially positioned with respect to thecentral opening.
 6. A moisture removing stack cap for a verticallyoriented, cylindrical engine air intake stack, comprising: a. acylindrical collector tube having a larger cross sectional dimensionthan the stack; b. means mounting said collector tube with a bottomportion thereof extending over a top end of said stack, providing anannular moisture collecting and discharging chamber between said tubeand said stack, a top portion of said tube extending above said stack;c. a stack cap base member, mounted on a top end of said tube, having acentral opening over said tube and wall flaring upwardly and outwardlyfrom said central opening, said wall having air intake openings thereinand terminating in a peripheral flange; d. dome-like stack cap covermember having a peripheral flange positioned over the flange of saidbase member, thereby forming an air flow chamber between said basemember and cover member; e. a plurality of air directing vanes eachhaving a flat horizontally extending connector portion positionedbetween said flanges, and a vertically positioned blade portionextending therefrom toward said central opening in a plane generallytangential with respect to said central opening, said vanes being evenlyspaced around the periphery of said stack cap; and f. means for tightlyclamping said flanges together to frictionally retain said connectorportions of said vanes therebetween, said vanes causing said air torotate as it passes into and downwardly through said collector tubethereby causing water into the air to impinge on the walls of said tubeand flow downwardly into said annular chamber.
 7. A moisture removingstack cap having a genrally cylindrically shaped collector tube withfirst and second end portions, said first end portion being adapted tobe mounted over a vertically oriented engine air intake stack, saidsecond end portion extending vertically upwardly when mounted and havinga smooth interior cylindrically shaped wall surface extending to anupper end of said tube, said stack cap including a base member having acentral opening of approximately the same diameter as the interiordiameter of said tube, means connecting said upper end of said tubedirectly to an edge of said central opening to provide a smooth air flowpath into said tube, said base member further including a wall flaringoutwardly from said central opening with air intake openings therein andterminating a peripheral edge, and said stack cap including a covermember having a peripheral edge connected to the peripheral edge of saidbase member, forming a chamber between said base member and cover memberpermitting air to flow from said air intake openings throug said chamberto said tube, a plurality of spaced air directing vanes secured to saidstack cap and positioned in said chamber between said air intakeopenings and said central opening to rotate the air as it passes intoand downwardly through said collector tube thereby causing moisture inthe air to impinge on and flow down the smooth interior wall surface ofsaid tube to separate the moisture from the air stream.